Method of forming convenience closure for container body

ABSTRACT

This application discloses a metallic convenience closure of the full panel tear out type for a container body, in which the closure upstanding side wall which perimetrically surrounds the central closure panel is provided with an inwardly extending protective bead. This bead is spaced above and extends generally parallel to the closure central panel. The score line which circumscribes the removable portion of the closure panel is located entirely radially outwardly of the bead, and therefore the sharp edge which is formed along such score line when the removable portion is removed is in non-cutting relationship with the hand of a person manually emptying the contents of the associated container. The closure is provided with a removal tab, the nose of which is located in the space between the closure panel and the protective bead. The protective bead also serves to radially stiffen the associated container, and a closure with such bead may be used to particular advantage with a semi-rigid container body, e.g., a composite, laminated container body deriving its strength principally from one or more cylindrically wound fiberboard plys or laminations.

United States Patent [1 1 3,705,563

Elser 1 Dec. 12, 1972 [54] METHOD OF FORMING Primary Examiner-Charles W. Lanham CONVENIENCE CLOSURE FOR Assistant ExaminerMichael J. Keenan CONTAINER BODY Attorney-E. J. Holler and Thomas A. Meehan [72] Inventor: William F. Elser, Toledo, Ohio [57] ABSTRACT.

[73] Assignee: Owens-Illinois, Inc.

Elser ..220/27 This application discloses a metallic convenience closure of the full panel tear out type for a container body, in which the closure upstanding side wall which perimetrically surrounds the central closure panel is provided with an inwardly extending protective bead. This bead is spaced above and extends generally parallel to the closure central panel. The score line which circumscribes the removable portion of the closure panel is located entirely radially outwardly of the bead, and therefore the sharp edge which is formed along such score line when the removable portion is removed is in non-cutting relationship with the hand of a person manually emptying the contents of the associated container. The closure is provided with a removal tab, the nose of which is located in the space between the closure panel and the protective bead. The protective bead also serves to radially stiffen the associated container, and a closure with such bead may be used to particular advantage with a semi-rigid container body, e.g., a composite, laminated container body deriving its strength principally from one or more cylindrically wound fiberboard plys or laminations.

1 Claim, 7 Drawing Figures mimgn uac 12 m2 3. 7 05. 563

sum 2 or 2 INVENTOR.

\IJ\LJ AM FT ELSER.

ljkwaah a g li uzr- METHOD OF FORMING CONVENIENCE CLOSURE FOR CONTAINER BODY This application is a division of Ser. No. 808,022 filed Mar. 17, 1969, now abandoned.

BACKGROUND OFTHE INVENTION In the packaging field, there has recently been a very rapid growth in popularity in convenience closures for 5 problem.

cans and other types of containers, i.e., closures which m can be opened manually withoutthe use ofia separate instrument. The self-opening feature is normally obtained by providing an element of the closure, e.g., the relatively flat central panel of a can closure, with a removable portion which iscircumscribed by a tear line, formed by weakening such element along such line. as by scoring. The circumscribed removable portion. is removable from the closure by tearing it from the remainder of the closure, and a tab or other grasping means is normally attached to the removable portion to initiate the severing or tearing of the material at a predetermined location on the tear line by movement of the tab relative to, the closure panel, and to complete the tearing or severing of the closure alongthetear line by providing means to grasp the removable portion to pull it away from the rest of the closure.

Convenience closures as above described are customarily constructed of metal, .as non-metallic materials do not normally have enough strength toprovide adequate safety against accidentalopening in the region of the weakened tear line. Aluminum is an especially popular metal for this purpose as it has sufficient strength to safeguard against accidental opening of the closure and insufficient strength to resist tearing or severing once the intended removal of the removable portion of the closure has been initiated. In any event, however, metallic convenience closures, including aluminum convenience closures, are characterized by a rather sharp edge which is left at the tear line afterthe removable portion of the closure has been removed. This sharp edge can pose a safety problemwith respect to the danger of cutting the hand of a user in closures of the full panel pull-out type which are of increasing popularity as can closures for cans used in the packaging of products which are customarily manually removed from their container, e.g., food shortening and snack food items.

According to the present invention, however, the hand of theuser of a manually emptying container with a metallic convenience closure of the full panel pull out type is protected from cutting by the sharp edge, formed in the closure panel after the removable portion has been removed, by a smooth surfaced bead which extends radially inwardly from the closure side wall to a location which is entirely radially inwardly of the tear line of the closure. To make sure that the bead is entirely radially inwardly of the tear line, it is necessary that the bead be spaced above the closure panel by a distance sufficient to receive the terminal tear-initiating portion of a removal tab. Otherwise, the tear line, at least at the location where severing is to be initiated, would have to be located at least slightly radially inwardly of the inwardly extending bead, to prevent interfe rence between the bead and the tear-initiating portion of the tab means. Any portion of the tear line which is located radially inwardly of the closure side wall bead will, of course, after removal of the remova- As an added benefit of the use of aclosure sidewall bead, it has been found that such bead radially stiffens the closure, and this property. can be exploited to particular advantage in closures for semi-rigid, container 1 bodies formed of laminated composite construction,

viz. the so-called fiber-cans. With respect to such containers, it has heretofore often been, necessary to use extra heavy metal stock in forming the closure to impart adequate radial rigidity to the finished container. when such a composite container is provided with a closure according to the present invention, the closure maybe formed from metal which is thinner than the. metal required for container rigidity which is used in conventional closures for such containers.

Accordingly, it is an object of this invention to, provide a method for forming a metallic closure.

Further objects and a better understanding of the present invention will be apparent from the following description of the drawing, the detailed description of the invention, and the claims.

DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view, in cross section, of a closure according to the present invention;

FIG. 2 is an elevational view, partly in cross section, of a cylindrical container having a closure of the type shown in FIG. I affixed to the upper end thereof;

FIG. 3 is a plan view of the container of FIG. 2;

FIG. 4 is a fragmentary view, at enlarged scale, of a portion of the body of a container with which a closure of the type shown in FIG. 1 can be employed to particular advantage; and

FIGS. 5-7 are fragmentary elevational sectional views showing successive steps in a method by which a closure of the type shown in FIG. 1 can be formed.

DETAILED DESCRIPTION OF THE INVENTION A metallic convenience closure according to the present invention, noted generally be reference character 11 in FIG. 1, comprises a generally flat central panel 12 adapted to span the opening of an associated container body. Central panel 12 is perimetrically surrounded by an upstanding wall 13, commonly referred to as a chuck wall in the trade, which is formed in integrally with central panel 12 and which is adapted to fit snugly along the inside surface of the end portion of an associated container body. Upstanding wall 13 terminates in a generally radially outwardly extending curled flange 14, which :is formed integrally with panel 12 and wall 13, and which is adapted to be assembled to the end portion of an associated container body in liquid-tight relationship by a known technique commonly referred to as double seaming.

Closure 11 is referred to as a convenience closure because a portion of the central panel 12, shown as portion 12a, is manually removable from the remainder thereof, without the need for a separate instrument or tool. Removable panel portion 12a of closure 11 in the present invention is of the same shape as the interior of the container to which closure 11 is intended to be affixed, most commonly circular as shown, and is almost as large as the interior of such container. Convenience closure 11 thereby is of the full panel pull-out type, as other closures of this type are commonly called. Removable panel portion 12a of closure 11 is removable from the remainder of the central panel 12 by tearing or severing along an endless tear line which is defined by score line means 15, most commonly comprising an endless score line.

Removably portion 12a of closure panel 12 is provided with an elongate removal tab 16 which is attached, at a location intermediate its ends, to portion 12a by riveting, preferably by an integral rivet 12b formed from the metal of the closure panel, as is well understood in the art. Removal tab 16, which is shown in FIG. 3 is being constructed generally in the shape of a T, although other popular styles of removal tabs would, of course, be satisfactory for the purpose, has its forward nose or extremity 16a disposed adjacent to, and slightly above, a portion of score line means 15. Initiation of the tearing or severing of closure panel 12 along score line means 15 is effected by manually lifting the remote or head end 16b of tab 16 to rotate the tab about rivet 12b in a limited arc in a plane normal to the general plane of central panel 12, thereby to depress nose 16a into severing relationship with a portion of score line means 15. Thereafter, the severing of the central panel along score line means 15, may be continued by grasping head end 16b of tab 16 and pulling it generally upwardly away from the remainder of the closure 11. When the severing is complete, the removable portion 12a, with tab means 16 still attached thereto may be discarded.

A full panel pull out convenience closure as above described may be used to particular advantage in relationship to a container for the packaging of a product of a type which is commonly manually removed from its container, for example, food shortening and various snack food items such as salted nuts. For such an application, however, it is important to protect the hand of the user of the associated container from being cut or scratched by the sharp edge which is inherently left along score line 15 in a metallic closure after removable panel 12a is removed there-from. According to the present invention, the sharp edge is protected from contact with the users hand by a smooth surfaced bead 17 of circumferentially endless character which extends inwardly from the side wall 13 of closure 11 to a location which is at least slightly inwardly of all portions of score line means. For example, in a closure intended for use with a NO. 502 cylindrical container body of composite construction, satisfactory protection of the hand of a user from the sharp edge surrounding a 4.860 inch diameter container opening can be obtained by means of a bead the inner nose of which defines a circular opening 4.834 inch diameter, with its center vertically aligned with the center of the container openmg.

Bead 17, which may be formed in an initially straight closure side wall by a technique which is subsequently discussed in greater detail, must be spaced above the plane of closure panel 12 by a distance sufficient to accommodate the tear initiating nose portion 164 of tab 16, for example by a distance in the range of 0.016 0.024 inch depending on the type of tab employed.

Otherwise, score line means 15, at least in the region where severing is initiated, and in all regions where a circular score line is employed, could not be positioned radially outwardly of bead 17. Without such positioning of the score line means 15 relative to bead 17, all, or at least a portion, of the sharp edge left along the score line would be in position to. injure the hand or fingers of a person using the associated container.

A closure 11, as above-described, may be affixed to an open end of a cylindrical container body, designated generally by reference character 21 in FIG. 2. As is shown in FIG. 2, closure 11 is affixed to container body 21 by means of a conventional double seam 22, which is formed by folding the flange 14 of closure 11 around a folded back terminal portion of the container body and by tightly crimping together the interengaged portions of the closure and container body. The other end of container body 21, shown as the lower end, is also closed, as by means of a conventional metallic closure 23 affixed thereto by means of double seaming, it being noted that one or the other of closures 11 and 23, usually conventional closure 23, is not seamed onto the container body until after the single-ended body is filled with the product to be packaged (not shown).

Container body 21 may be considered to be of any conventional container body-forming material, including aluminum, tinplate and composite fiber-foil or fiber-film laminates. A metallic convenience closure 11, as described above, can be used with any of such container body types and in each case it will provide the safety features noted above. However, an additional advantage may be realized when such a closure is used with a container body 11 which is formed of composite fiber laminates, the portion of a wall of which is shown in section in FIG. 4. Such a container body, which lacks the rigidity under radial load of a metallic container body, is formed by cylindrical winding e.g.,

by spirally winding, in known fashion, one or more body plys or lamina, shown as two plys 26 and 27, an outer impervious liner label ply or lamina 24 and an inner impervious liner ply or lamina 25.

It has frequently been found that container bodies formed of such composite, laminated construction required heavier gage closures than were required for metallic container bodies of similar size, in order to provide added rigidity to the completed container. A metallic convenience closure 11 according to the present invention, however, has added rigidity in the radial direction due to the presence of radially extending head 17. Because of this added rigidity of the closure, it is expected that it will be possible to use closure stock of reduced thickness to obtain comparable rigidity in containers with composite laminated container bodies to the rigidity obtained with conventional metallic convenience closures for such purpose of greater thickness. For example, a convenience closure formed of 0.008 or 0.009 inch thick aluminum sheet, according to the present invention, is expected to be satisfactory for No. 401 cylindrical can body of laminated composite construction, (compared with a conventional sheet thickness of 0.010 inch for this size closure) and a closure formed of 0.010 inch thick aluminum sheet, according to the present invention, is expected to be satisfactory for a NO. 502 cylindrical can body (compared with a conventional sheet thickness of 0.012 inch for this size closure).

, B is formed in the sidewall C of closure blank by tangentially engaging the sidewall between counterrotating tools D and E which have, respectively, engaging bead-forming male and female tool surfaces F and G, respectively. After forming a loose shallow bead B in closure blank A by the procedure illustrated in FIG. 5, the pre-beaded blank is transferred to a scoring tool F for scoring the blank along an endless circular line G, the diameter of which is less than the inner diameter of the loose shallow bead B, as is shown in FIG. 6. Thereupon, the pre-beaded and scored blank is transferred to a press which serves to press or collapse the loose, shallow bead to a tight, deep bead H, the inner diameter of which is less than the diameter of bead B. This pressing action is obtained by the action of die members J, K, L and M respectively, as is shown in FIG. 7. J and K exert a pressing action upon the closure flange and bead. Distance x between K and J is adjustable and controls the degree of bead collapse and the distance or clearance between the bead and panel L is a springbacked flange support ring which prevents distortion of the flange 14 during the pressing action. M is the fixed support plate for the end during the pressing action.

The best mode known to me to carry out this inven- ZIOI tion has been described above in terms sufficiently full, clear, concise and exact as to enable any person skilled in the art to make and use the same. It is understood, however, that is is within my contemplation that certain modifications of the above-described mode of practicing the invention can be made by a skilled artisan without departing from the scope of the invention and it is, therefore, desired to limit the invention only in accordance with the appended claims. For example, it is expressly contemplated that the invention can be applied to non-circular closures, for example, to closures for generally oval shaped containers, such as sardine containers and pre-cooked ham containers.

I claim:

l. The method of forming a metallic closure comprising the steps of: providing a metallic closure blank having a central panel and a parimetrical upstanding wall surrounding the central panel and formed integrally therewith; forming a loose, shallow head in the upstanding wall; forming score line means defining an endless severing line in the central panel, all portions of said score line means being spaced radially inwardly from the innennost portion of the head by a small distance; and deforming said loose head to form a tight, deep bead axially spaced apart from said score line means, the innermost portion of which extends radially inwardly of the score line means, so that all portions of the score line means are protected 'by said tight bead. 

1. The method of forming a metallic closure comprising the steps of: providing a metallic closure blank having a central panel and a parimetrical upstanding wall surrounding the central panel and formed integrally therewith; forming a loose, shallow bead in the upstanding wall; forming score line means defining an endless severing line in the central panel, all portions of said score line means being spaced radially inwardly from the innermost portion of the bead by a small distance; and deforming said loose bead to form a tight, deep bead axially spaced apart from said score line means, the innermost portion of which extends radially inwardly of the score line means, so that all portions of the score line means are protected by said tight bead. 